1. Field of the Invention
The present general inventive concept relates to an image forming apparatus that uses an electrophotographic process, such as a copy machine and/or a printer. More particularly, the present general inventive concept relates to a process cartridge detachably mounted in the image forming apparatus.
2. Description of the Related Art
A process cartridge is an assembly of a developing unit and a toner unit. The process cartridge includes a photosensitive medium, an electrifying unit, the developing unit, and a cleaning unit integrally formed to be detachably connected with respect to a main assembly of an image forming apparatus.
Electrophotographic image forming apparatuses typically use the process cartridge, since the process cartridge is easily operated and does not require special skills.
The process cartridge comprises a developing cartridge, and a toner cartridge detachably mounted to the developing cartridge to supply a toner to the developing cartridge. FIG. 1 illustrates an image forming apparatus including a main body 1 that uses a process cartridge 10.
As illustrated in FIG. 1, the main body 1 has a cartridge seating portion 2 for mounting the process cartridge 10 therein. The process cartridge 10 comprises a developing cartridge 20 and a toner cartridge 30. The toner cartridge 30 and the developing cartridge 20 are illustrated separately in FIGS. 2A and 2B, respectively. FIG. 3 illustrates both the toner cartridge 30 and the developing cartridge 20 detachably mounted to each other as the process cartridge 10.
The developing cartridge 20 comprises a developing cartridge frame 21 having a toner inlet 21a. Other developing parts of the developing cartridge 20, such as a photosensitive medium rotatably mounted to the cartridge frame 21, are omitted from the figures.
The toner cartridge 30 comprises a toner cartridge frame 31 having a toner supply port 31a. The toner cartridge 30 comprises additional parts such as an agitator for agitating the toner stored in a toner chamber formed therein and for moving the toner toward the toner supply port 31a. However, these additional parts are also omitted from the figures.
As illustrated in FIG. 3, the developing cartridge 20 and the toner cartridge 30 are detachably mounted to each other. The toner can be supplied by connecting the toner inlet 21a of the developing cartridge 20 to the toner supply port 31a of the toner cartridge 30 to correspond with each other.
The developing cartridge 20 and the toner cartridge 30 can be respectively mounted to the main body 1 of the image forming apparatus such that only the toner cartridge 30 need be replaced when the toner is used up. The toner inlet 21a of the developing cartridge 20 is initially blocked by a removable packaging lid, such as a plastic film, but is opened for use by removing the packaging lid. As a result, the toner inlet 21a is left open during and between uses of the image forming apparatus. When the toner inlet 21a is connected with the toner cartridge 30, a sponge seal attached around the toner inlet 21a is able to prevent the toner from leaking from the developing cartridge 20.
However, when the toner cartridge 30 is disconnected from the developing cartridge 20 (e.g., in a state that the process cartridge 10 is removed from the main body 1), the toner in the developing cartridge 20 may leak through the toner inlet 21a, which is in an open state. The leakage of the toner may lower the density of an image, and deteriorate image quality. Therefore, preventing the toner leakage from the developing cartridge 20 is necessary in order to improve the image quality.